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PubMed1996

Bilateral interactions in saccade programming. A saccade-latency study.

Subjects were required to make a saccade to a target appearing randomly 4 degree to the left or right of the current fixation position (1280 trials per experiment). Location cues were used to direct visual attention and start saccade preparation to one of the two locations before target onset. When the cue indicated the target location (valid trials), the generation of express saccades (visually guided saccades with latencies around 100 ms) was strongly facilitated. When the opposite location was cued (invalid trials), express saccades were abolished and replaced by a population of mainly fast-regular saccades (latencies around 150 ms). This was found with a peripheral cue independently of whether the fixation point was removed before target onset (gap condition; experiment 1) or remained on throughout the trial (overlap condition; experiment 2). The same pattern also was observed with a central cue that did not involve any visual stimulation at a peripheral location (experiment 3). In the case where the primary saccade was executed in response to the cue and the target appeared at the opposite location, continuous amplitude transition functions were observed: starting at about 60-70 ms from target onset onward, the amplitude of the cue-elicited saccades continuously decreased from 4 degree to values below 1 degree. The results are explained by a fixation-gating model, according to which the antagonism between fixation and saccade activity gives rise to multimodal distributions of saccade latencies. It is argued that allocation of visual attention and saccade preparation to one location entails a successive disengagement of the fixation system controlling saccade preparation within the hemifield to which the saccade is prepared and a partial engagement of the opposite fixation system.

Adult↗
PubMed2025

Triage and workflow optimization with artificial intelligence in pediatric imaging.

Artificial intelligence (AI) is being increasingly utilized in various aspects by the radiology department. With an ever-increasing burden on the healthcare system, particularly in emergency units, the need to incorporate AI in patient triage and workflow optimization cannot be overstated. Machine learning (ML)-based algorithms form the core of AI-based software, aiding healthcare professionals at nearly every step in delivering appropriate patient care. Regarding the radiology section of the hospital, AI-based algorithms have proven exceptionally useful in assisting radiologists and technicians with image acquisition. From accurate clinical referrals to scheduling computed tomography/magnetic resonance imaging scan appointments, from ensuring the lowest radiation exposure to offering timely follow-up reminders, ML-based software has indeed revolutionized the concept of modern image acquisition, especially in the pediatric radiology section. Although the implementation of these algorithms is swift, several technical challenges and the limited availability of pediatric datasets preclude their widespread use. The utility of multimodal pediatric datasets, which combine imaging, genomics, and clinical data, for comprehensive AI triage models can help AI systems evolve toward greater adaptability and integration, resulting in enhanced efficiency, reduced turnaround times, and improved patient outcomes in pediatric radiology departments in the future. In this article, we highlight and review the utility of AI and machine learning-based algorithms in efficiently aiding triage and streamlining the workflow in the pediatric radiology section, thereby ensuring an overall improvement in the departmental workflow.

Triage↗
PubMed2003

Applying exercise to the management of fibromyalgia.

Fibromyalgia, chronic fatigue syndrome, and related illnesses fall under the spectrum of chronic multisymptom illnesses (CMI). This constellation of syndromes often is defined by chronic pain, unremitting fatigue, cognitive difficulties, and various other symptoms. In treating these illnesses, pharmacotherapy generally is the mode of choice, with exercise being overlooked often. However, research has shown that exercise is quite beneficial in reducing pain and fatigue in this population and should be included as part of a multimodal therapy regimen. This article reviews the exercise and CMI literature and provides a model for applying these evidence-based guidelines to a clinical population.

Adaptation, Physiological↗
PubMed1999

Behavioral interventions in the diagnosis, treatment and rehabilitation of children with cancer.

Behavioral interventions used to reduce distress and increase cooperation in children undergoing cancer treatment incorporate: contingency management, cognitive/attentional distraction, hypnosis, systematic desensitization, modeling and behavioral rehearsal. In most cases clinical interventions integrate these procedures into a multimodal intervention package. Although in most behavioral interventions the 'therapist' is a nurse, social worker or child psychologist; parents often take an active role in behavioral intervention. Early return to school can 'normalize' the child's life in the midst of coping with cancer and can promote optimal rehabilitation. More research is needed on the integration of behavioral methods with other therapeutic methods (e.g., pharmacologic). Indeed, research in this area of pediatric oncology must be continuously updated as advances in other areas may affect clinical decisions regarding preferred psychosocial intervention methods.

Adaptation, Psychological↗
PubMed2004

Too much lumping in ischemic stroke - a new classification.

BACKGROUND: The heterogeneity of ischemic stroke syndromes with treatment of disparate categories may be a factor in clinical stroke trial failure. Recent advances include a multitude of stroke investigative modalities that are noninvasive, allowing more precise mechanistic determination. MATERIAL/METHODS: We retrospectively analyzed our young stroke patient population for stroke etiology according to the TOAST classification with five different etiological groups. Patients were assessed quantitatively according to the National Institute of Health Stroke Scale for neurological deficit and Rankin Scale for neurological handicap. Investigations included laboratory, Doppler sonograms of the cervicocephalic vessels, cardiac echocardiography and multimodality magnetic resonance imaging in all patients. Statistical analysis was performed, using a logit model for nominal response: log piJ/piJ)=alphaj+betajX. RESULTS: Amongst young stroke patients (n=133, women n=72) causes included other (n=77/119;65%), large vessel disease (LVD) (n=8/119;7%), small vessel disease (SVD) (n=17/119;14%), unknown (n=3/119;2%) and cardiac (n=14/119;12%). Within the other category at least 20 different etiologies were delineated. There were significant differences among the various categories (multinomial distribution with equal probabilities p=<0.0001). CONCLUSIONS: We recommend an expanded classification for stroke to include large vessel cerebrovascular disease, small vessel cerebrovascular disease, cardiogenic, dissection, prothrombotic states, migraine induced, cerebral venous thrombosis, vasculitides, vasculopathy other, miscellaneous and unknown.

Adolescent↗
PubMed2001

Multimodality image registration quality assurance for conformal three-dimensional treatment planning.

PURPOSE: We present a quality assurance methodology to determine the accuracy of multimodality image registration and fusion for the purpose of conformal three-dimensional and intensity-modulated radiation therapy treatment planning. Registration and fusion accuracy between any combination of computed tomography (CT), magnetic resonance (MR), and positron emission computed tomography (PET) imaging studies can be evaluated. METHODS AND MATERIALS: A commercial anthropomorphic head phantom filled with water and containing CT, MR, and PET visible targets was modified to evaluate the accuracy of multimodality image registration and fusion software. For MR and PET imaging, the water inside the phantom was doped with CuNO(3) and 18F-fluorodeoxyglucose (18F-FDG), respectively. Targets consisting of plastic spheres and pins were distributed throughout the cranium section of the phantom. Each target sphere had a conical-shaped bore with its apex at the center of the sphere. The pins had a conical extension or indentation at the free end. The contours of the spheres, sphere centers, and pin tips were used as anatomic landmark models for image registration, which was performed using affine coordinate-transformation tools provided in a commercial multimodality image registration/fusion software package. Four sets of phantom image studies were obtained: primary CT, secondary CT with different phantom immobilization, MR, and PET study. A novel CT, MR, and PET external fiducial marking system was also tested. RESULTS: The registration of CT/CT, CT/MR, and CT/PET images allowed correlation of anatomic landmarks to within 2 mm, verifying the accuracy of the registration software and spatial fidelity of the four multimodality image sets. CONCLUSIONS: This straightforward phantom-based quality assurance of the image registration and fusion process can be used in a routine clinical setting or for providing a working image set for development of the image registration and fusion process and new software.

Head and Neck Neoplasms↗
PubMed1982

A cognitive-psychological model of REM dream production.

Based on the methodological assumption that cognitive-psychological study of dream processes (psychoneirics) can be pursued in like manner as in cognitive-psychological study of speech processes (psycholinguistics) and on the substantive assumption that speech and dreaming may share some common production routines, a cognitive-psychological model of dream formation is proposed. A generalized psycholinguistic model of speech production is presented, and then each sequential stage of that model is examined for its aptness to the process of dream production. It is concluded that there are major differences between speech and dream production at both the input and the output levels (message formulation in the linguistic sense is absent in the instigation of the dream; the dream itself is a multimodal perceptual simulation), but it is proposed that midrange stages of speech and dream production may be largely identical. This model is shown to be consistent with various formal properties of the dream, including its central paradox of controlled formal organization in the face of contents that may be "senseless," trivial, or obscure. The model also is shown to suggest several new research paradigms that might be employed both to test its own utility and to generate data more generally relevant to the question of how mental functions are organized during rapid eye movement sleep.

Cognition↗
PubMed2001

TLM simulation of microwave sintering of ceramics using SiC stimulus.

Microwave heating technology is becoming a successful technique used for sintering ceramic materials. However, various aspects of sintering experiments, such as the use of process stimulus and the preparation of sample arrangements, depend mainly on human expertise. The Transmission Line Matrix (TLM) method is first used to solve the combined electromagnetic and thermal equations modeling microwave heating of dielectric materials. It is then used to simulate microwave sintering of a low-loss ceramic material in a multimode microwave cavity. To enhance the microwave sintering process, Silicon Carbid (SiC) was first used as a susceptor and in a picket fence arrangement. As multiple samples may be processed in a microwave oven, the TLM was used to model such a process, and the introduction of SiC as a stimulus was also examined. Results show the importance of the stimulus thickness and configuration on the uniformity and density of the electromagnetic field distribution and, therefore, on the power dissipation within the ceramic load.

Aluminum Oxide↗
PubMed2006

Optimization of the robustness of multimodal networks.

We investigate the robustness against both random and targeted node removal of networks in which P(k), the distribution of nodes with degree k, is a multimodal distribution, [formula--see text] with k(i) proportional to b -(i-1) and Dirac's delta function delta (x). We refer to this type of network as a scale-free multimodal network. For m=2, the network is a bimodal network; in the limit m approaches infinity, the network models a scale-free network. We calculate and optimize the robustness for given values of the number of modes m, the total number of nodes N, and the average degree , using analytical formulas for the random and targeted node removal thresholds for network collapse. We find, when N>>1, that (i) the robustness against random and targeted node removal for this multimodal network is controlled by a single combination of variables, N(1/m-1), (ii) the robustness of the multimodal network against targeted node removal decreases rapidly when the number of modes becomes larger than a critical value that is of the order of 1n N, and (iii) the values of exponent lambda(opt) that characterizes the scale-free degree distribution of the multimodal network that maximize the robustness against both random and targeted node removal fall between 2.5 and 3.

Journal Article↗
PubMed2001

[Physical and methodological aspects of multimodality imaging and principles of treatment planning in 3D conformal radiotherapy].

The recent evolutions of the imaging modalities, the dose calculation models, the linear accelerators and the portal imaging permit to improve the quality of the conformal radiation therapy treatment planning. With DICOM protocols, the acquired imaging data coming from different modalities are treated by performant image fusion algorithms and yield more precise target volumes and organs at risk. The transformation of the clinical target volumes (CTV) to planning target volumes (PTV) can be realised using advanced probabilistic techniques based on clinical experience. The treatment plans evaluation is based on the dose volume histograms. Their precision and clinical relevance are improved by the multi-modality imaging and the advanced dose calculation models. The introduction of the inverse planning systems permitting to realise modulated intensity radiation therapy generates highly conformal dose distributions. All the previously cited complex techniques require the application of rigorous quality assurance programs.

Dose Fractionation, Radiation↗
PubMed1991

[Use of ribonuclease in multimodal treatment of acute pancreatitis].

The method of intraductal administration of ribonuclease as a therapeutic measure was developed on an experimental model of acute pancreatitis in albino rats. Morphological and biochemical examination showed that intraductal administration of ribonuclease in a dose of 0.5 mg produces a positive therapeutic effect, which allowed the method to be applied in complex treatment of 33 patients with various forms of acute pancreatitis. Administration of ribonuclease into the pancreatic duct relieved the attack of pain and reduced the level of lipo- and proteolytic enzymes in blood. No complications were encountered in endoscopic cannulation of the main pancreatic duct and subsequent administration of ribonuclease.

Acute Disease↗
PubMed2003

Numerical wave optical analysis of microlens array telescopes and comparison with experimental results.

We present a numerical wave optical model to describe the complex behavior of coaxial and decentered microlens-array-based telescopes illuminated by an incoherent angular spectrum of plane waves. With the use of this model we have been able to observe major performance differences between Galilean and Keplerian setups, which to our knowledge were not described before. The results of the simulations are compared with experimental results; the images of multimode fiber end faces are characterized with respect to transfer efficiency and intensity distribution. The results are also explained by use of modified existing analytical models.

Journal Article↗
PubMed2005

A behavioral and pharmacological validation of the acetone spray test in gerbils with a chronic constriction injury.

UNLABELLED: Cold and mechanical allodynia are important symptoms in patients with neuropathic pain. The study of cold allodynia in animals can help us to understand the underlying pathophysiological mechanisms of neuropathic pain and to validate drugs. The evaluation of cold allodynia in gerbils with a chronic constriction injury of the sciatic nerve on the cold plate is not always stable. We developed a new application method of acetone using a specific spray technique with an Eppendorf multistepper pipette. The chronic constriction injury of the sciatic nerve in gerbils resulted in a long-lasting mechanical and acetone spray-induced hyperreactivity throughout the testing period, which is clearly different from what was seen in sham-operated animals. The acetone spray test incorporates a multimodal stimulus different from direct cold stimulation. The reactivity to the acetone spray coincides in time and strength with the reactivity observed in mechanical allodynia in gerbils and with mechanical and thermal allodynia in other species. Furthermore, a pharmacological validation of the acetone spray test by different reference compounds was performed. Different compounds effective in neuropathic pain models in rodents influence the hyperreactivity to the acetone spray after acute and chronic administration. This study indicates that the multimodal acetone spray test is a valuable tool in the study of neuropathic pain in rodents. IMPLICATIONS: The acetone spray test is a multimodal and valuable tool in the evaluation of neuropathic pain behavior in gerbils.

Acetone↗
PubMed1994

Structural equation analyses of clinical subpopulation differences and comparative treatment outcomes: characterizing the daily lives of drug addicts.

The use of structural equation modeling (SEM) is illustrated for comparative treatment outcome research conducted with heterogeneous clinical subpopulations within large multimodality treatment settings. All analyses are accomplished with SEM analogs of more familiar classical multivariate techniques. The effect of the early period of treatment on the daily lives of 486 clients in two drug abuse treatment modalities (methadone maintenance and outpatient counseling) is evaluated. Structured means analysis is used to assess initial differences between modalities on the latent means of 6 latent constructs reflecting daily life. The effect of treatment modality and attrition from the program on daily life latent constructs is evaluated while initial selection differences are statistically controlled. Effect sizes are computed on the basis of SEM parameter estimates. The advantage of SEM over classic multivariate approaches for correcting for selection bias when assessing comparative outcomes is explained.

Activities of Daily Living↗
PubMed2002

Design of microchannel free-space optical interconnects based on vertical-cavity surface-emitting laser arrays.

We investigate the design of free-space optical interconnects (FSOIs) based on arrays of vertical-cavity surface-emitting lasers (VCSELs), microlenses, and photodetectors. We explain the effect of the modal structure of a multimode VCSEL beam on the performance of a FSOI with microchannel architecture. A Gaussian-beam diffraction model is used in combination with the experimentally obtained spectrally resolved VCSEL beam profiles to determine the optical channel crosstalk and the signal-to-noise ratio (SNR) in the system. The dependence of the SNR on the feature parameters of a FSOI is investigated. We found that the presence of higher-order modes reduces the SNR and the maximum feasible interconnect distance. We also found that the positioning of a VCSEL array relative to the transmitter microlens has a significant impact on the SNR and the maximum feasible interconnect distance. Our analysis shows that the departure from the traditional confocal system yields several advantages including the extended interconnect distance and/or improved SNR. The results show that FSOIs based on multimode VCSELs can be efficiently utilized in both chip-level and board-level interconnects.

Journal Article↗
PubMed1996

Statistics for investigation of multimodal MR imaging data and an application to multiple sclerosis patients.

Magnetic resonance spectroscopy can image axonal damage specifically based on changes in N-acetyl aspartate (NAA), a neuronal marker. We have developed statistical methods for multimodal analysis of MR spectroscopic images. These methods, which are extensions of mixed-effect models, have allowed us to quantify differences in images from different subgroups of patients with multiple sclerosis (MS) and to determine the dependence of chemical pathology on clinical disability, duration of disease and lesions on T2-weighted MRI. Statistical power was improved by using all reliable resonance intensities in the spectroscopic images while taking into consideration the intra-subject correlations. We studied 17 normal subjects, 14 patients with relapsing remitting (RR) MS and 21 patients with chronic progressive (CP) MS. The ratio of resonance intensities of N-acetylaspartate over creatine (Cr) was found to be significantly lower than normal in normal appearing white matter (NAWM) of both RR and CP patients (19.6% in RR, 28.8% in CP), NAA/Cr was decreased even more in MS plaques than in NAWM (44.2% in RR, 17.7% in CP), NAA/Cr was correlated with clinical disability (p < 0.02) and disease duration (p < 0.1). Our results suggest that, in this setting, MRS reflects accumulated neuronal loss or damage and can be used as a measure of disease severity. The methods developed provide opportunities to evaluate the relationship between inflammation, demyelination, axonal loss and clinical disability in future studies.

Aspartic Acid↗
PubMed1996

Improved target volume definition in radiosurgery of arteriovenous malformations by stereotactic correlation of MRA, MRI, blood bolus tagging, and functional MRI.

In this methodological paper the authors report the stereotactic correlation of different magnetic resonance imaging (MRI) techniques [MR angiography (MRA), MRI, blood bolus tagging (STAR), and functional MRI] in 10 patients with cerebral arteriovenous malformations (AVM) and its application in precision radiotherapy planning. The patient's head was fixed in a stereotactic localization system that is usable at the MR and the linear accelerator installations. By phantom measurements different materials (steel, aluminium, titanium, plastic, wood, ceramics) used for the stereotactic system were tested for mechanical stability and geometrical MR image distortion. All metallic stereotactic rings (closed rings made of massive metal) led to a more or less dramatic geometrical distortion and signal cancellation in the MR images. The best properties-nearly no distortion and high mechanical stability-are provided by a ceramic ring. If necessary, the remaining geometrical MR image distortion can be "corrected" (reducing displacements to the size of a pixel) by calculations based on modeling the distortion as a fourth-order two-dimensional polynomial. Using this method multimodality matching can be performed automatically as long as all images are acquired in the same examination and the patient is sufficiently immobilized. Precise definition of the target volume could be performed by the radiotherapist either directly in MR images or in calculated projection MR angiograms obtained by a maximum-intensity projection algorithm. As a result, information about the hemodynamics of the AVM was provided by a three-dimensional (3D) phase-contrast flow measurement and a dynamic MRA with the STAR technique leading to an improved definition of the size of the nidus, the origin of the feeding arteries, and the pattern of the venous drainage. In addition, functional MRI was performed in patients with lesions close to the primary motor cortex area leading to an improved definition of structures at risk for high-dose application in radiosurgery. The different imaging techniques of MR provide a sensitive, noninvasive, 3D method for defining target volume, critical structures, and for calculating dose distributions for radiosurgery of cerebral arteriovenous malformations, because dose calculation of radiosurgery at sufficient accuracy can be based on 3D MR data of the geometrical conformation of the patient's head.

Algorithms↗